The present invention is generally related to integrated circuits and more particularly to a combined antenna and circuit structure.
Wireless communication devices and services have proliferated in recent years. Affordability and convenient access to personal communication services including cellular telephony (analog and digital), paging and emerging so-called personal communication services (PCS) has fueled the continued growth of a worldwide mobile communication industry. Numerous other wireless applications and areas show promise for sustained growth including radio frequency identification (RFID), various satellite-based communications, personal assistants, local area networks, device portability such as through the bluetooth(trademark) protocol, etc.
Of course, this growth has been accompanied by the continuous development and improvement of integrated circuits. High levels of integration continue to be demanded. Radio frequency integrated circuits (RFIC) and monolithic microwave integrated circuits (MMIC) are evidence of this trend. RFIC and MMIC are now commonly further packaged with VLSI digital signal processors and microprocessors on circuit boards and in advanced multi-chip modules (MCM) which are characterized by mounting and interconnecting multiple bare chips on a substrate, base material or laminate. Mixed-signal integration in which various different functions such as RF, low-frequency analog and digital functions are desirable. At least one National Science Foundation (NSF) project is believed to be initiated to investigate methods for the direct integration of PCS band antennas on mixed-technology integrated circuits.
While single chip integration of the various analog, digital and RF functions remains desirable for reasons of reliability, cost, product performance, manufacturing and size among others, previous attempts at such combinations have generally not yielded satisfactory results. Low noise operation is a requirement in the successful transmission and reception of signals. However, transistors are noteworthy for their inherent noise creation. This is particularly acute in silicon CMOS technologies, which are known to have high noise factors at low frequencies, and in silicon bipolar technologies, which exhibit moderate noise factors at high frequencies. Undesirable coupling may generally be referred to herein as cross talk.
Proximal placement of radiating and receiving antenna structures with respect to the digital and analog circuitry has proven to be quite a challenge in the industry. Shielding techniques have generally proven to be unsatisfactory due to processing limitations with respect to the relatively large surface area required to be covered. Additionally, shielding has performance drawbacks and is an efficiency drain due to at least the undesirable image currents that are established.
Therefore, it is one object of the present invention to provide a high level of integration of the various functions of a wireless device.
It is a further object of the present invention to provide an on-chip antenna exhibiting satisfactory cross talk characteristics.
It is a further object of the present invention to provide an on-chip antenna exhibiting improved efficiency characteristics.
It is a further object of the present invention to provide an on-chip antenna in accordance with the preceding objects utilizing conventional CMOS compatible manufacturing processing methods.
In accordance with these and other objects and advantages, the present invention comprises a single-chip integrated circuit comprising a base portion including an integrated circuit, a substantially planar antenna and a shielding layer between the base portion and antenna. The shielding layer is characterized by a plurality of mutually isolated regions.